18F-FDG PET/CT for evaluation of metastases in nonsmall cell lung cancer on the efficacy of immunotherapy

Objective This study aimed to investigate the relationship between F-18-fluorodeoxyglucose PET/computed tomography (F-18-FDG PET/CT) metabolic parameters and clinical benefit and prognosis in nonsmall cell lung cancer (NSCLC).Methods In total, 34 advanced NSCLC patients who received F-18-FDG PET/CT before immunotherapy were retrospectively included in this study. All patients were divided into two groups, the clinical benefit (CB) group and the no-clinical benefit (no-CB) group, based on the efficacy of evaluation after 6 months of treatment. Also clinical information, characteristics of metastases, survival, PD-L1 expression level and glucose metabolic parameters were evaluated.Results Finally, 24 patients were in the CB group, and 10 patients were in the no-CB group. There was a significant difference between the CB group and the no-CB group in TNM stages (P = 0.005), visceral and bone metastasis (P = 0.031), metabolic tumor volume of primary lesion (MTV-P; P = 0.003), the metabolic tumor volume of whole-body (MTVwb; P = 0.005) and total lesion glycolysis of whole-body (TLGwb, P = 0.015). However, for patient outcomes, the independent prognostic factors associated with progression free survival were TNM stage (HR = 0.113; 95% CI, 0.029-0.439; P = 0.002), TLG-P (HR = 0.085; 95% CI, 0.018-0.402; P = 0.002) and TLG-LN (HR = 0.068; 95% CI, 0.015-0.308; P = 0.000), and the TLG-LN (HR = 0.242; 95% CI, 0.066-0.879; P = 0.002) was the independent prognostic factor associated with overall survival.Conclusions Metastatic lesion burden evaluated by F-18-FDG PET/ CT can predict response to immunotherapy in advanced NSCLC patients, in which lymph node metastasis lesion metabolic burden is a meaningful predictor, but a large multicenter trial is still needed to validate this conclusion.